DUCTS FOR SUPPLYING PRESSURIZED FLUIDS

CONDUITS POUR L'APPROVISIONNEMENT DE FLUIDES PRESSURISES

English Abstract

A duct with outlets for delivering a conveyed fluid, particularly for systems
for
conditioning civil or industrial premises, comprising a hollow body that can
be connected to a
source of pressurized fluid and has, along its extension, at least one outlet
for delivering the
conveyed fluid. The delivery outlet is delimited, along at least one of its
sides, by a flap that can
flex elastically due to the action of the fluid conveyed by the duct to vary
the passage section of
the fluid through the delivery outlet as the difference in pressure between
the inside of the hollow
body and the outside varies.

Claims

9
THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR
PRIVILEGES IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A duct with outlets for delivering a conveyed fluid, for conditioning civil
or industrial
premises, which comprises
.cndot. a hollow body that can be connected to a source of pressurized fluid;
and
.cndot. at least one delivery outlet for delivering said fluid, delimited,
along at least one of its
sides, by a flap that can flex elastically due to the action of said fluid to
vary the passage
section of the fluid through said delivery outlet as the difference in
pressure between the
inside of said hollow body and the outside varies,
wherein said hollow body has, at least at said delivery outlet, a portion made
of elastically
flexible material and wherein said delivery outlet is formed by slits which
are provided in said
portion made of elastically flexible material and delimit the at least one
elastically flexible flap
along the perimeter of said delivery duct.
2. A duct in accordance to claim 1, wherein said slits extend from a same
point.
3. A duct in accordance to claim 1, wherein said slits extend from a perimeter
of a hole.
4. A duct in accordance to claim 1, wherein said slits form sector shaped
flaps which are
distributed around a circular region.
5. A duct in accordance to claim 1, wherein said slits form sector-shaped
flaps which are
arranged around a circular region that is crossed by a hole.
6. A duct in accordance to claim 1, wherein said slits are distributed
symmetrically with respect
to a point.

10
7. A duct in accordance to claim 1, wherein said slits are distributed
symmetrically with respect
to an axis.
8. A duct in accordance to claim 1, wherein said slits are arranged
asymmetrically so as to
provide a different deformability of the sides of the delivery outlet as the
pressure of said fluid
varies.
9. A duct in accordance to claim 1, wherein said hollow body is constituted by
a tubular body
made of resin-treated fabric.

Description

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1
The present invention relates to a duct with outlets
for delivering a conveyed fluid, particularly for systems
for air-conditioning civil or industrial premises.
For conditioning civil or industrial premises ducts are
used, which are embedded in the masonry of the buildings or
placed outside the masonry, and by means of which the
conditioning fluid, constituted by hot or cold air, is
conveyed and distributed in the various areas of the rooms
to be conditioned.
l0 In particular, ducts are known which are constituted by
tubes made of resin-treated fabric, are suspended at a
certain height from the floor of the room, and have, along
their extension, multiple fluid delivery outlets which are
spaced one from another according to the requirements of the
distribution of the fluid within the room.
Said delivery outlets are generally constituted by
circular or square holes which are obtained by removing
portions of the walls of the tubular body made of resin-
treated fabric. In this manner, the delivery outlets have a
fluid passage section that is constant and independent of
the variation in the difference in pressure between the
fluid inside the duct and the outside. Due to this fact, the
conditions at which the fluid is delivered vary as the
pressure of the fluid inside the duct varies. High pressures
and high flow-rates of the fluid conveyed along the duct in
fact lead to high speeds of the fluid delivered through the
outlets; such speeds can be unpleasant for the occupants of

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the space being air-conditioned. On the other hand, this
problem is not easy to solve since operating with larger
outlets, which would have the advantage of reducing the
fluid delivery speed, would cause the drawback of
eliminating the effects of conditioning when the system must
operate at low flow-rates and low pressures.
Another problem arising from delivery outlets provided
as holes having a practically constant cross-section resides
in the high load losses that occur in the fluid stream when
1o it passes through said outlets. Vortical motions in f act
occur at the sides that delimit the outlet and the fluid
stream contracts as it leaves the outlet, leading to high
pressure losses that negatively affect the operating costs
of the system, since they entail additional energy
consumption to compensate for them.
Another drawback that can be observed in ducts with
delivery outlets constituted by circular or square holes is
that it is impossible to deliver the fluid in a direction
which is substantially at right angles to the longitudinal
2o axis of the duct, since fluid delivery is unavoidably
affected by the direction of the flow of the fluid inside
the duct.
A principal aim of the present invention is to solve
the drawbacks described above, providing a duct with
delivery outlets that allow to deliver high fluid flow-rates
but with very low pressure losses and thus with reduced
energy consumption with respect to known ducts.
Within the scope of this aim, an object of the invention
is to provide a duct with delivery outlets that is capable

~1~4~.~~.
3
of reducing the fluid delivery speed at high flow-rates
without however eliminating the effects of delivery at low
flow-rates.
Another object of the invention is to provide a duct
with delivery outlets that allow, if required, a particular
orientation of the delivered fluid.
This aim, these objects, and others which will become
apparent hereinafter are achieved by a duct with outlets for
delivering the conveyed fluid, particularly for systems for
to air-conditioning civil or industrial premises, which
comprises a hollow body that can be connected to a source of
pressurized fluid and has, along its extension, at least one
outlet for delivering said fluid, characterized in that said
delivery outlet is delimited, along at least one of its
sides, by a flap that can flex elastically due to the action
of said fluid to vary the passage section of the fluid
through said delivery outlet as the difference in pressure
between the inside of said hollow body and the outside
varies.
2o Further characteristics and advantages of the invention
will become apparent from the description of some preferred
but not exclusive embodiments of the duct according to the
invention, illustrated only by way of non-limitative example
in the accompanying drawings, wherein:
figure 1 is a schematic perspective view of a portion
of a duct according to the invention, with three delivery
outlets;
figure 2 is an enlarged-scale axial sectional view of a
portion of the duct of figure 1, taken at a delivery outlet;

figure 3 is a view of a different embodiment of the
duct according to the invention;
figures 4 to 16 are views of various types of delivery
outlet of the duct according to the invention.
With reference to the above figures, the duct according
to the invention, generally designated by the reference
numeral 1, comprises a hollow body 2 which can be connected
in a per se known manner to a source of pressurized fluid,
such as for example a pump 3, by means of which the fluid to
1o be conveyed is fed into the hollow body 2. Along the duct
there is at least one delivery outlet 4 through which the
fluid conveyed inside the hollow body 2 is delivered
outside. According to the invention, said delivery outlet 4
is delimited, along at least one of its sides, by a flap
that can flex elastically by virtue of the action of the
fluid conveyed in the hollow body 2 in order to vary the
passage section of the fluid through the delivery outlet as
the difference in pressure between the inside of the duct
and the outside varies.
2o More particularly, the hollow body can be constituted
by a tubular body made of resin-treated fabric, as shown in
particular in figures 1 and 2, or can be constituted by a
rigid body, designated by the reference numeral 2a in figure
3.
In any case, at the delivery outlets the hollow body
has at least one portion that is made of elastically
flexible material, and the delivery outlet is formed exactly
in this portion made of elastically flexible material. If
the hollow body is constituted by a tubular body made of

X144131
resin-treated fabric, elastic flexibility is ensured by the
very material of which the hollow body is made, whereas if
the hollow body is constituted by a rigid tubular body, a
portion 5, constituted for example by a sheet made of
5 elastically flexible material in which the delivery outlet
is formed, will be provided.
Conveniently, the delivery outlet is formed by slits
which are formed directly in the walls of the hollow body 2,
if said body is made of elastically flexible material, or
to are formed in the portion 5 made of elastically flexible
material which is applied to the hollow body 2a. These slits
in practice form the delivery outlet with one or more
perimetric elastically flexible flaps 40.
The slits may have various shapes and arrangements
according to the requirements.
As shown in figures 4 and 5, the delivery outlet can be
formed by slits 7 and 8 that extend from a same point and
are distributed symmetrically around said point.
As shown in figure 6, the slits 9 can also be arranged
2o symmetrically with respect to an axis rather than a point.
Furthermore, as shown in particular in figures 7, 8,
and 9, the slits 30 can start from a hole 10, 11, and 12
rather than from a point, and the hole may be circular,
square, rectangular, and so forth.
Figure 10 illustrates a further embodiment of the
outlet in the duct according to the invention. According to
this embodiment, the outlet is formed by slits 13 which
delimit sector-like flaps 14 that extend radially outwards
from a circular region 15.
Figure 11 illustrates still a further different

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6
embodiment, similar to the one shown in the preceding
figure, in which a hole 16 is formed in the circular region
15.
Figure 12 illustrates another different embodiment of
the outlet in the duct according to the invention, wherein
the outlet is formed by two slits 17 and 18, one of which
starts from the median point of the other.
In figure 13, the outlet is formed by a slit 19 that
runs from a median region of the straight side of a hole 20
to shaped like a circular portion.
Figure 14 illustrates an outlet which is simply
constituted by a slit 21 with two portions 21a and 21b lying
at right angles to each other.
Figure 15 illustrates an outlet which is constituted by
a slit 22 that extends from the base of a rectangular hole
23.
Figure 16 illustrates an outlet which is constituted by
a rectangular hole 24 with a flap formed by two slits 25a
and 25b which run from two vertices of the hole 24 and
2o delimit a flap 26 that affects a single side of the hole.
Figures 12 to 16 illustrate outlets which are
constituted by slits which are asymmetrical, so as to obtain
a different deformability of the sides of the outlet as the
pressure of the fluid conveyed inside the duct varies.
The slits that form the delivery outlets can be
provided using known technologies, such as for example
punching, laser cutting, melting, molding, blanking,
coupling, etcetera.
In practice, as shown in particular in figure 2, the
outlets of the duct according to the invention can vary, by

21~~1~~.
virtue of the elastic flexibility of the flap or flaps which
are formed by the slits and affect one or more of their
sides, the passage section of the fluid during delivery
according to the difference in pressure between the fluid
inside the duct and the outside. In this manner, when high
flow-rates of fluid with high pressures must be delivered,
the delivery outlet, under the thrust of the fluid itself,
assumes the condition in which its passage section is
largest, thus reducing the speed at which the fluid is
1o delivered and avoiding unpleasant effects on the occupants
of the air-conditioned space. Vice versa, when low flow-
rates of fluid must be delivered, or when the fluid is
conveyed along the duct at low pressure, the delivery outlet
can have a reduced fluid passage section, so as to still
allow the delivered fluid to reach the desired distances
from the duct.
It should be noted that the flexibility of the flaps
that delimit the delivery outlets also allows to
significantly reduce losses at the perimetric sides of the
2o delivery outlet, with advantages as regards energy
consumption.
In practice it has been observed that the duct with
delivery outlets according to the invention fully achieves
the intended aim, since it automatically modulates the
delivery speed of the fluid, reducing pressure losses at the
delivery outlets, and thus reducing the energy consumption
required to convey and distribute the fluid.
A further advantage of the duct with delivery outlets
according to the invention is that it is possible to shape
3o the outlets so that the configuration of the outlet varies

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8
as the pressure of the fluid inside the duct varies, thus
allowing to orientate as required the flow of the fluid that
leaves the duct.
Although the duct with delivery outlets according to
the invention has been conceived in particular for systems
for air-conditioning civil or industrial premises, it can
nonetheless also be used for conveying and distributing any
type of fluid in the gaseous or liquid phase or in a mixed
liquid-gaseous phase at any temperature and pressure.
The duct with delivery outlets thus conceived is
susceptible of numerous modifications and variations, all of
which are within the scope of the inventive concept; all the
details may furthermore be replaced with other technically
equivalent elements.
In practice, the materials employed, as well as the
contingent shapes and dimensions, may be any according to
the requirements and the state of the art.

Representative Drawing